He came to spotlight during the 2014 Occupy protests when he was beaten by seven Hong Kong Police officers in Tamar Park, Admiralty, after being arrested in a police clearance operation after he poured foul-smelling liquid over eleven officers on 15 October 2014. He was noted with extensive injuries including swelling and bruising of the forehead, upper face, and chin; bruising of the neck; bruising of the clavicle; circular reddish bruises all over the chest; bruising of both sides of the abdomen; bruising of the back; bruising of the left wrist; abrasions and bruising of the left arm and hand; and abrasion of the left knee.[3] Doctors testified that the distinctive circular bruises were likely caused by forceful jabbing of retracted police batons.[3]

In October 2015, Tsang was arrested for one count of assaulting police and four counts of obstructing public officers,[4] along with the seven officers who were charged with the assault on him.[5] In May 2016 Tsang was found guilty of three counts of assaulting police and resisting arrest, and was sentenced to five weeks in jail. Principal Magistrate Peter Law noted that Tsang did not intend to hurt the police, but stated that it was a serious crime and Tsang showed no remorse.[6] The seven police officers were also found guilty of assault occasioning actual bodily harm on Tsang and were sentenced to two years imprisonment.[7]